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Stock Issued During Period, Value, Issuance Of Common Stock Upon Vesting Of Restricted Stock Units BofA securities Inc. BofA Securities Inc [Member] BofA Securities, Inc [Member] Maria Dobek Maria Dobek [Member] Maria Dobek. Common stock reserved for issuance Common Stock, Capital Shares Reserved for Future Issuance Schedule of Accrued Liabilities [Table Text Block] Schedule of Accrued Expenses Preferred stock, shares issued Preferred Stock, Shares Issued Preferred Stock, Shares Issued, Total Operating Lease, Liability Total operating lease liabilities Total operating lease liabilities Maximum payment to buy out royalty obligation Maximum Payment To Buy Out Royalty Obligation Maximum payment to buy out royalty obligation. 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Stock Issued During Period, Value, Exercise of Pre-funded Common Stock Warrants Exercise of pre-funded common stock warrants Change in accounting principle, ASU, Adoption date Accrued compensation Employee-related Liabilities, Current Employee-related Liabilities, Current, Total Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Earnings Per Share [Abstract] Short-Term Investments Investment, Policy [Policy Text Block] Summary of Stock Option Activity Share-Based Payment Arrangement, Option, Activity [Table Text Block] Lessee operating lease liability payments due after year four. Lessee Operating Lease Liability Payments Due After Year Four Thereafter Lessee, Operating Lease, Liability, to be Paid, Year Four 2030 Plan Name Plan Name [Axis] Equity [Abstract] Share-Based Payment Arrangement [Member] ESPP Employee Stock Purchase Plan Shares Stockholders' Equity Equity [Text Block] Cash flows from financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Entity Tax Identification Number Entity Tax Identification Number Equity Component Equity Component [Domain] Comprehensive loss Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Entity Address, City or Town Entity Address, City or Town Unpaid property and equipment Capital Expenditures Incurred but Not yet Paid Restricted Cash, Noncurrent Restricted cash Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Investments Classified by Contractual Maturity Date [Table Text Block] Schedule of Contractual Maturities of Available-for-sale Debt Securities Commercial Paper Commercial Paper [Member] Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Antidilutive Security, Excluded EPS Calculation [Table] Transition Agreement [Member] Transition agreement. Transition Agreement Deferred revenue current Current portion of deferred revenue Contract with Customer, Liability, Current Statement [Table] Statement [Table] Deferred Revenue, Current Deferred Revenue, Current, Total Deferred revenue current Current portion of deferred revenue Common Stock Options Outstanding Common Stock Options Outstanding [Member] Common stock options outstanding. 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Percentage Of Annual Increase In Common Stock Available For Issuance Percentage of annual increase in common stock available for issuance Restricted Stock Units Outstanding [Member] RSUs Outstanding Restricted Stock Units Outstanding Restricted stock units outstanding. Construction in Progress [Member] Assets not placed in service Cash paid Operating Lease, Lease Income, Lease Payments Unvested Restricted Stock Units [Member] Unvested restricted stock units. Unvested RSUs Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Excluding Exchange Rate Effect, Including Discontinued Operation Net decrease in cash, cash equivalents and restricted cash Merck Agreement First Collaboration Target [Member] Merck agreement first collaboration target. Merck Agreement First Collaboration Target Weighted- Average Grant Date Fair Value per Share, Granted Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Current assets: Assets, Current [Abstract] Document Fiscal Year Focus Document Fiscal Year Focus Percentage of eligible earnings withheld to purchase shares of common stock Percentage Of Eligible Earnings Withheld To Purchase Shares Of Common Stock Percentage of eligible earnings withheld to purchase shares of common stock. Accretion of discounts on investments, net Accretion (Amortization) of Discounts and Premiums, Investments Common stock, shares outstanding Common Stock, Shares, Outstanding Common Stock, Shares, Outstanding, Beginning Balance Common Stock, Shares, Outstanding, Ending Balance Financial Instruments [Domain] Stock issued during period, shares, issuance of common stock upon vesting of restricted stock units. 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Schedule of Prepaid Expenses and Other Current Assets [Table Text Block] Schedule of Prepaid Expenses and Other Current Assets Operating Lease, Liability, Noncurrent Operating lease liabilities, net of current portion Revenue recognized Contract with Customer, Liability, Revenue Recognized Total minimum lease payments Lessee, Operating Lease, Liability, to be Paid Other Accrued Liabilities, Current Other accrued expenses Additional paid-in capital Additional Paid in Capital, Common Stock Additional Paid in Capital, Common Stock, Beginning Balance Additional Paid in Capital, Common Stock, Ending Balance Security Exchange Name Security Exchange Name New Accounting Pronouncements, Policy [Policy Text Block] Recent Accounting Pronouncements/Accounting Pronouncements Pending Adoption Class of Warrant or Right, Exercise Price of Warrants or Rights Price of warrants sold per share Accrued interest receivable Financing Receivable, Accrued Interest, before Allowance for Credit Loss Entity Address, State or Province Entity Address, State or Province Unrecognized stock-based compensation cost, weighted-average period of recognition Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized Shares authorized for issuance Schedule of Available-for-Sale Debt Securities in an Unrealized Loss Position Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value [Table Text Block] Non-refundable and non-creditable upfront fee. Non-Refundable and Non-Creditable Upfront Fee Non-refundable and non-creditable upfront fee Operating Lease, Right-of-Use Asset Operating lease right-of-use assets Amendment Flag Amendment Flag Schedule Of Research And Development Arrangement Contract To Perform For Others [Table] Research and Development, Contract to Perform for Others [Table] Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Table] Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table] City Area Code City Area Code Shares issued under employee stock purchase plan Stock Issued During Period, Value, Employee Stock Purchase Plan Transition and Consulting Agreement [Member] Transition and consulting agreement. Transition and Consulting Agreement Unvested Common Stock Unvested Common Stock [Member] Unvested common stock. Organization, Consolidation and Presentation of Financial Statements [Abstract] Comprehensive Loss Comprehensive Income, Policy [Policy Text Block] Proceeds from Issuance of Common Stock Gross proceeds from issuance of common stock Unvested stock liabilities. Unvested Stock Liabilities [Abstract] Unvested Stock Liabilities Available-for-sale debt securities number of position gross unrealized loss Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions Computer Equipment and Software Computer Equipment [Member] Percentage of number of common stock shares Percentage Of Number Of Common Stock Shares Percentage of number of common stock shares. Common stock, par value Common Stock, Par or Stated Value Per Share Weighted- Average Remaining Contractual Term, Exercisable Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted-Average Remaining Contractual Term Lessee, Leases [Policy Text Block] Leases Number of Options, Vested and expected to vest Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Liquidity and Capital Resources Liquidity And Capital Resources Policy [Text Block] Liquidity and Capital Resources. Total current liabilities Liabilities, Current Total property and equipment Property, Plant, and Equipment, before Accumulated Depreciation, Depletion, and Amortization Property, Plant and Equipment, Gross, Total Property, Plant and Equipment, Gross, Beginning Balance Property, Plant and Equipment, Gross, Ending Balance Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Including Discontinued Operation Total cash and cash equivalents and restricted cash Total cash and cash equivalents and restricted cash Cash, cash equivalents and restricted cash - beginning of year Cash, cash equivalents and restricted cash - end of period Pre-funded warrants. Prefunded Warrants [Member] Pre-funded Warrants Jefferies Group LLC [Member] Jefferies Group LLC [Member] Jefferies Group LLC. Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Weighted-Average Grant Date Fair Value Minimum increase in shares reserved for issuance Minimum Increase In Shares Reserved For Issuance Minimum increase in shares reserved for issuance. Debt Securities, Available-for-Sale [Table Text Block] Summary of Short-Term Investments Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Trading Symbol Trading Symbol Issuance costs Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs Schedule of Property and Equipment, Net Property, Plant, and Equipment [Table Text Block] Fair Value Measurement Fair Value Measurement, Policy [Policy Text Block] Collaboration revenue Revenue from Contract with Customer, Including Assessed Tax Revenue Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period Granted Number of RSUs, Granted Entity Emerging Growth Company Entity Emerging Growth Company Additional Paid-in Capital [Member] Additional Paid-in Capital [Member] Plan Name Plan Name [Domain] Shares issued under employee stock purchase plan (in shares) Stock Issued During Period, Shares, Employee Stock Purchase Plans US Treasury Securities [Member] U.S. Treasury Securities U.S. Treasury Securities Total Intrinsic value of stock options exercised Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value Cover [Abstract] Commitments And Contingencies [Line Items] Commitments And Contingencies [Line Items] Commitments and Contingencies. Operating Lease, Weighted Average Remaining Lease Term Operating lease, weighted average remaining lease term Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block] Summary of RSU Activity Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated Other Comprehensive Income (Loss), Net of Tax, Total Accumulated other comprehensive income (loss) Concentrations of Credit Risk Concentration Risk, Credit Risk, Policy [Policy Text Block] Early exercised shares Share Based Compensation Arrangement By Share Based Payment Award Options Early Exercised Shares Share based compensation arrangement by share based payment award options early exercised shares. Stock-based compensation Share-Based Payment Arrangement, Noncash Expense Share-based Payment Arrangement, Noncash Expense, Total Proceeds from Maturities, Prepayments and Calls of Short-Term Investments Maturities of short-term investments Adjustments to reconcile net loss to net cash used in operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Short-term investments Short-Term Investments Short-term Investments, Total Cash and cash equivalents Cash and Cash Equivalent Cash and Cash Equivalents, at Carrying Value, Total Cash and Cash Equivalents, at Carrying Value, Beginning Balance Cash and Cash Equivalents, at Carrying Value, Ending Balance Net cash provided by financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Clinical Trial Expenses Clinical Trial Expenses [Policy Text Block] Clinical trial expenses. Payables and Accruals [Abstract] Number of Options, Forfeited or cancelled Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures in Period Number of Outstanding Options, Forfeited or cancelled Entity Filer Category Entity Filer Category Weighted- Average Exercise Price, Vested and expected to vest Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Upfront Payment Received Upfront payment received. Upfront payment received Increase (Decrease) in Accounts Receivable Accounts receivable Property and equipment, net Property, Plant and Equipment, Net, Beginning Balance Property, Plant and Equipment, Net, Ending Balance Property and equipment, net Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization 12 Months or Longer, Fair Value Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer Available-for-sale debt securities, in continuous unrealized loss position for 12 months or longer Shares, Outstanding Ending balance (in shares) Beginning balance (in shares) Number of Collaborative Arrangement Targets Number of Collaborative Arrangement Targets Number of collaboration targets Unvested stock liabilities vested shares. Unvested Stock Liabilities Vested Shares Vested shares Vested shares Entity Address, Postal Zip Code Entity Address, Postal Zip Code Statement of Financial Position [Abstract] Local Phone Number Local Phone Number